“I thank God that I’m a part of it, because I really don’t want anything else,” says Brewster from the show’s Los Angeles set, where she’s sporting a fake black eye, the result of a future episode’s tussle with a spree killer and a car crash.

“I don’t want to do movies. I don’t want to do another show. I just want to be here,” says Brewster, 40.

And why not? Where else could she fuel her passion for learning about serial killers and, like, breaking windows and stuff?

“One of my favorite things ever, was the episode where Morgan (Shemar Moore) and I break into a taxidermy shop and I smash a pane of glass in a door with my elbow,” she says.

“They gave me three panes of glass. I was able to do it three times and I loved it. I kept rewinding on my TiVo, like, ‘Yeah, I look kind of cool!’ ”

Although the glass was just sugar glass — a form of brittle sugar that breaks more easily than real glass, Brewster says, “You can still get cut by it.”

“When I smashed it, it cut my arm. I was like, ‘Yeah! I got a war wound!’ I thought it was cool.”

As enthusiastic as she is about breaking windows on the job, she’s ensured that the same thing can’t happen at her LA home. Three weeks after getting cast, Brewster says, “I installed bulletproof glass and did a bunch of other things that are non-residential. Pentagon-level countermeasures that I can’t talk about,” she adds with a laugh.

“I have bars on a lot of my windows and bulletproof laminate on whatever isn’t barred — and I live in a pretty safe neighborhood, too. I’m like the crazy lady who has done this stuff to her house!

“You know what? I live alone, I work on a show where I look at horrifying stuff everyday; it makes sense,” says the currently single actress. She adds: “I called it ‘research’ and wrote it off [on her taxes].”

Already well-versed about serial killers and stalkers — the result of being stalked when she hosted “The Paget Show,” a mid-’90s, San Francisco-based talk show — she admits that she “was profoundly affected when I joined ‘Criminal Minds.’ ”

“I read all the serial killer stuff, but I was only able to get my hands on civilian stuff. So when [‘Criminal’ executive producer] Ed Bernero gave me the real FBI textbooks, I was like, ‘This is great!’ — and it’s horrible.

“There’s a reason why civilians don’t have access to this stuff; they shouldn’t. Nobody should. I kind of wish I hadn’t read it; it was absolutely terrifying,” she says.

“It’s a bottomless pit, the horrors the human brain is capable of, if you’re a psychotic killer. There were about three weeks where I don’t think I slept well.”

For a change of pace, Brewster watches cooking shows, and hosts wine and cheese nights.

“People come over, and we watch things like ‘The Paul Lynde Halloween Special.’ I have a hot tub. Everybody puts on a bathing suit and we splash around.”

Having fun on the show also lightens the mood. “It’s the funniest set I’ve ever been on — and I’ve predominantly done comedies,” she says.

“The director will say, ‘Action!’ and we’re laughing until we put on a straight face and start doing dialogue. The moment they yell, ‘Cut,’ we all laugh and point at each other — ‘Nice eyebrow work, Shemar!’

“We call it ‘FB-Eyebrow.’ At the end of the scene, you cross you arms and go, ‘We’ve got to find him before he finds us,’ and then you raise one eyebrow.”

With the series’ 100th episode airing this week, it’s no surprise that CBS is eyeing a “Criminal Minds” spin-off.

“We’re calling it ‘Criminal Minds: Caliente.’ Like it’s going to be in Miami and everyone’s going to be 22 and super hot,” she says.

“Frankly, we’re jealous — it’s like mom and dad bringing home another baby: We want to be the only one.”